A promising new blood test could help detect concussion in patients up to a week after the injury occurred, according to a new study. The research, published online March 28 in JAMA Neurology, is significant because many people experience delayed symptoms and do not seek help immediately following a head injury.
“Symptoms of concussion, or of mild-to-moderate traumatic brain injury, can be subtle and are often delayed, in many cases by days,” lead author Linda Papa, MD, MSC, an emergency medicine physician and NIH-funded researcher at Orlando Health, said in a news release. “This [test] could provide doctors with an important tool for simply and accurately diagnosing those patients, particularly children, and making sure they are treated properly.”
It’s estimated that nearly 250,000 children – an average of 700 a day – are treated each year for concussions sustained while playing sports. Nearly all concussions in kids are diagnosed by observed symptoms such as vomiting or loss of balance, or by symptoms reported by the child, including blurred vision or headache. Neither, however, gives doctors an objective way to determine the severity of the injury.
The danger is that patients who are not diagnosed properly won’t receive appropriate treatment and will have long-term problems. Untreated or under-treated brain injuries can lead to prolonged bouts with headaches, dizziness, memory loss and depression.
“This test could take the guesswork out of making a diagnosis by allowing doctors to simply look for a specific biomarker in the blood,” explained Papa.
Biomarkers are molecules that can be measured to help doctors detect changes in the body related to injury and disease. For the study, Papa analyzed blood samples for the presence of the biomarker glial fibrillary acidic protein (GFAP). These proteins are found in glial cells, which surround neurons in the brain. When injury an occurs, GFAP is released into the bloodstream.
Papa and her colleagues analyzed the blood of 584 patients with trauma-related injuries who visited Orlando Regional Medical Center, a Level 1 trauma center, over a period of three years. Approximately half the patients had brain-related injuries and half had other traumas, including broken bones and chest injuries.
Everyone in the study had blood drawn within four hours of their injury. Blood tests were repeated every four hours for the first 24 hours and then twice a day for the next six days. By tracking changes in the levels of GFAP over time, the researchers could correlate the changes with the patients’ symptoms.
Findings showed that GFAP levels rose within the first hour after the injuries and peaked within 20 hours post-injury. After 20 hours, GFAP levels began to decline, but were still detectable seven days later. When cross-checked with CT scans, the blood test was able to detect mild-to-moderate brain injuries with up to 97 percent accuracy in patients 18 years and older.
The study authors suggested that the blood test could reduce the need for CT scans, currently the most precise way to diagnose brain injuries. CT scans are not only expensive, but are also associated with radiation exposure.
Knowing who has a more serious injury based on the blood test could help limit the number of unnecessary CT scans. “Physicians really want to minimize the amount of CTs in patients, especially children who are more sensitive to radiation and the side effects that can come with it. Fortunately, this simple blood test appears to give us nearly the same information as a CT scan,” Papa said.
“We have so many diagnostic blood tests for different parts of the body, like the heart, liver and kidneys, but there has never been a reliable blood test to identify trauma in the brain. We think this test could change that,” Papa added.